Synthetic drying oil



Patented June 8, 1948 2,443,079 sritrnsrrc DRYING on.

Ferdinand P." tto, Woodbury, N. J., assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application September 6, 1945, Serial No. 614,827

6 Claims.

- This invention relates generally to a process for producing cyclic olefinic hydrocarbons from aromatic hydrocarbons, and is more particularly concerned with a process for preparing synthetic drying oils from aromatic hydrocarbons.

It is well known in the art to produce synthetic drying oils by dehydrohalogenating halogenated mineral oils. Thus, it has been proposed to prepare synthetic drying oils by chlorinating mineral oils under various conditions and dechlorinating the chlorinated mineral oils thus obtained in accordance with a variety of procedures. However, the properties and behavior of these products have never been entirely satisfactory from a commercial standpoint and accordingly, they have not replaced to any'appreciable extent, the use of the well known drying oils obtained from vegetable sources.

I have discovered that it is possible to produce synthetic drying oils from mineral oils, which compare favorably with many of the drying oils 7 obtained from vegetable sources.

I have found that cyclic olefinic hydrocarbons possessing valuable drying oil properties may be obtained from aromatic hydrocarbons through a combination of treatments which will be described in detail hereinafter.

Accordingly, it is an object of the present invention to provide a synthetic drying oil. An-

other object is to provide a process for producing synthetic drying oils from mineral oils. A further object is to provide a process for producing synthetic drying oils from aromatic hydrocarbons. A more specific object is to produce synthetic drying oils from alkyl naphthalenes. An important object is to afford a process for producing cyclic olefinic hydrocarbons having valuable drying oil properties from aromatic hydrocarbons. A very important object is to provide a process for producing cyclic olefinic hydrocarbons having valuable drying oil properties from alkyl naphthalenes. Other objects and advantages of the present invention will become apparent to those skilled in the art from the following description.

Broadly stated, the present invention provides a process for producing cyclic olefinic hydrocarbons having valuable drying 011 properties, which comprises hydrogenaitng aromatic hydrocarbons to produce saturated cyclic hydrocarbons, halogenating the saturated hydrocarbons thus obsynthetic drying oils in accordance with my intained to produce halogenated saturated cyclic hydrocarbons, and dehydrohalogenating the halogenated saturated cyclic hydrocarbons to yield cyclic olefinic hydrocarbons.

vention, are the alkyl naphthalenes. and especially, the dimethyl and trimethyl naphthalenes. A preferred source of these dimethyl and trimethyl naphthalenes is the bottoms obtained in Houdry catalytic cracking and Thermofor catalytic cracking operations. As is well known to those familiar with the art, these bottoms, especially those obtained in multiple pass operations, are highly aromatic (over 80 per cent by volume) and are characterized by boiling ranges varying between about 440 F. and about 750 F. and specific gravities at F. of over 1.0. Certain fractions thereoi having boiling ranges varying between about 500 F. and about 600 F., and specific gravities at 60 F. of the order of about 0.98, consist mainly at least per cent and ordinarily (-100 per cent by volume) ofdimethyl and trimethyl naphthalenes. It must be clearly understood, however, that these bottoms constitute only preferred sources and that others are available, for example, coal tar fractions, as is well known in the art. These bottoms contain a large variety of compounds, such as polymethyl benzenes, naphthalene, methyl naphthalene, dimethyl naphthalene, trimethyl naphthalene, methyl anthracenes, acenaphthene, methyl fiuorenes, anthracene, and other polycyclic aromatic hydrocarbons. However, tests have shown that the products having the most desirable drying oil properties are obtained by utilizing the fractions containing the alkyl naphthalenes, and more particularly, those containing the dimethyl and trimethyl naphthalenes. Accordingly, the utilization of these fractions in my process must be considered a preferred embodiment of the present invention. 'It must be distinctly under stood, however, that the entire bottoms referred to hereinbefore may be utilized. However, the products thus obtained although possessing drying oil properties, will be somewhat inferior to those obtained when my preferred charge stocks are employed.

In accordance with the present invention, the general procedure followed for producing the synthetic drying oils is as follows:

The charge stocks referred to hereinbefore are subjected to exhaustive catalytic hydrogenation under pressure, as is well known in the art, until the product contains no appreciable quantities (not more than by volume) of aromatic hydrocarbons. When the charge stocks consist mainly of alkyl naphthalenes, more particularly, dimethyl and trimethyl naphthalenes, the product will consist largely of alkyl decalins. The product of the hydrogenation operation is then subjected to halogenation, as is likewise well known in the art. When the product of the hydrogenation operation consists largely of alkyl decalins, the halogenation treatment will produce haloalkyl decalins. Finally, the product of the halogenation treatment is subjected to a catalytic dehydrohalogenation until the evolution of hydrogen halide ceases for allpractical purposes.

The product of the dehydrohalogenation treatment will comprise cyclic oleiinic hydrocarbons. This product is filtered through an absorbent clay, such as Super-Filtrol, to produce the synthetic drying oil. If desired, prior to filtration, the product may be diluted with a solvent, such as benzene or petroleum ether, to facilitate the filtration. A liquid film of this product will dry into a solid, elastic film. The drying time can be reduced materially by incorporating any of the well known metallic driers into the synthetic drying oil.

The conditions of catalytic hydrogenation employed in the process of my invention are those used in the prior art for efiecting the catalytic hydrogenation of aromatic hydrocarbons. Accordingly, the hydrogenation step is carried out in the presence of a hydrogenation catalyst, chosen, as is well known to those familiar with the art, with respect to the type of charge stock used and the optimum conditions of its employment, so as to permit hydrogenation at a practical rate under reaction conditions at which undesirable side reactions such as decomposition, dealkylation, and the like, are substantially precluded. The product of the hydrogenation operation should contain no more than about 5% by volume aromatic hydrocarbons.

Any of the well known hydrogenation catalysts may be used, and excellent results are obtained with the relatively inexpensive and easily regenerated base nickel catalysts which possess the desired degree of hydrogenation activity. Nickel, cobalt, copper, and chromium may be mentioned by way of non-limiting examples of suitable base metal hydrogenation catalysts. The oxides of the metals such as nickel, zirconium, thorium, and mixtures comprising two or more metal oxides with one or more base metals are also useful per se as hydrogenation catalysts or as constituents or hydrogenation catalytic mixtures. Although, I prefer to use the base metals or alloys thereof as hydrogenation catalysts, I may use noble metal hydrogenation catalysts such as silver, platinum, gold and the like, or even alloys thereof.

The hydrogenation catalysts may be prepared in accordance with any suitable procedure and may be used in conjunction with relatively inert carriers such as charcoal, silica gel, clays, pumice, and the like, and/or with small amounts of substances of promoters, for example, the oxides and oxygen-containing salts of the alkaline earth metals, aluminum, manganese, etc., as is well known to those familiar with the art.

I have found that the charge stocks referred to hereinbefore can be hydrogenated with excellent results by employing nickel-containing hydrogenation catalysts. These catalysts can be prepared conveniently and economically by effecting the thermal decomposition and/or reduction of nickel salts of volatile organic acids 4 through heating in an atmosphere of an inert gas or of hydrogen at temperatures ofthe order -of about 300 C.

The amounts of hydrogenation catalyst to be employed will depend upon the nature and amount of material to be hydrogenated and upon the activity of the catalyst. When finely divided nickel is used the amounts employed may vary between about 1% and about 5% by weight of the charge stocks. However, considerable variation in these proportions may be made.

The temperature at which hydrogenation is carried out depends upon the particular type of charge stock, upon the activity of the hydrogenation catalyst employed, upon the contact time, and, to a, certain extent, upon the pressure used. Generally speaking, the undesirable side reactions referred to hereinbefore are accelerated at the higher temperatures, hence, I ordinarily prefer to operate at temperatures not exceeding about 500 C. When nickel-containing and hydrogenation-catalysts of comparable catalytic activity are employed, temperatures varying between about 150 C. and about 300 C. should .be used. With sorr eof the noble metal catalysts, as for example, colloidal palladium, temperatures as low as room temperatures are suitable. Generally, however, temperatures higher than about 100 C. are desirable.

The hydrogenation reaction may be efiected in the liquid or vapor phase. Therefore, the pressure to be used depends upon the temperature, upon whether the hydrogenation is carried out in the liquid phase or vapor phase, and also to a certain extent upon the catalyst selected. Accordingly, the pressure may vary between atmospheric and 1500 pounds per square inch and even higher if desired.

Substantially pure hydrogen or hydrogen-containing materials from any available source may be employed. The presence of substantially inert substances is not detrimental and it is rather advantageous as an aid to temperature control.

The hydrogenation may, be carried out as a continuous or batch operation. In continuous operations, the charge stock together with hydrogen or a suitable hydrogen-containing gas are passed under the selected pressure and at a suitable rate into contact with a hydrogenation catalyst in a reaction zone maintained at the desired reaction temperature. In batch operation, a suitable reaction vessel may be an autoclave equipped with a mechanical stirrer to maintain the catalyst in suspension. The hydrogenation catalyst may be added to the reaction vessel before, during or after the introduction therein of the reactants, the latter being charged thereinto severally or in admixture.

Generally speaking, the conditions and procedure of halogenation employed in the process of the present invention are those used in the prior art for effecting the halogenation of saturated hydrocarbons. Accordingly. depending upon the activity of the halogenating agent, as is well known in the art, the halogenation may be carried out at low temperatures in the presence of diffused light or no light, in the presence of halogenation catalysts; or at higher temperatures in the presence of bright light.

For reasons of economy, I prefer to use chlorine or gases containing chlorine as the halogenating agent, and in the preferred embodiment of my invention, the chlorination is carried out at temperatures varying between about 20 C. and about C., and preferably, at temperatures varying between a'bout 30 C. and 50 C. These temperatures appear to be more suitable for my purpose than the higher temperatures, in that the products obtained after dehydrohalogenation possess a higher degree of unsaturation. For example, when the alkyl decalins obtained by hydrogenating charge stocks containing largely dimethyl and trimethyl naphthalenes, are subjected to chlorination at temperatures within the preferred chlorination temperature range, until the product contains between about 25% and 35% by weight of chlorine, iodine numbers of 100-140 are ordinarily obtained after dehydrochlorination. On the other hand, when higher chlorination temperatures are used, 1. e., higher than about 80 C., the degree of unsaturation of the dehydrochlorinated products is appreciably lower.

In accordance with my invention, the halogenation or preferably, the chlorination, of the products of the hydrogenation operation is carried out for a sufficient length of time such that the halogenated or chlorinated product contains between about 25% and about 35% by weight of halogen, or preferably, chlorine. I have found that when the product of the halogenation operation contains more than between about 25% and about 35% by weight of halogen or chlorine, the products obtained from the dehydrohalogenation operation possess a degree of unsaturation which is considerably lower; thereby detracting from the drying oil properties of the products. Tests have shown that, other variables remaining constant, the best results are obtained when the halogenation is carried out to an extent such that the-product of the halogenation operation has a halogen content varying between about 29% and about 32% by weight.

The products of the halogenation operation which in the preferred embodiment of the present invention, consist largely of haloalkyl decalins, and preferably, chloralkyl decalins, are subjected to a dehydrohalogen-ation step.

Generally speaking, the conditions and procedure of dehydrohalogenation employed in the process of the present invention are those used in the prior art for effecting the dehydrohalogenation of halogenated hydrocarbons. Accordingly, the dehydrohalogenation may be carried out in the presence of dehydrohalogen-ation catalysts (catalytic dehydrohalogenation) such as zinc dust, iron powder, calcium hydroxide, pyridine, or clays; or with heat alone. However, since, asv is well known to those familiar with the art, the temperatures required to achieve dehydrohalogenation in the absence of dehydrohalogenation catalysts (thermal dehydroh-alogena-tion) are somewhat higher, thereby producing darker products, I prefer to use catalytic dehydrohalogenation and for reasons of economy and practical operation, I especially prefer to use lime as the dehydrohalogenation catalyst. There appears to be nothing critical about the amounts of dehydrohalogenation catalyst employed. From a practical viewpoint, the amounts used should be such as to permit dehydrohalogenation at a practical rate considering the nature of the material undergoing treatment and the dehydrohalogenating activity of the catalyst.

, The temperatures employed in the catalytic dehydrohalogenation operation ordinarily vary between about 175 C. and about250 C., preferably, between about 200 C. and about 230 C., and

generally speaking, the dehydrohalogenation is carried out for a suflicient period of time to remove substantially all the halogens from the material undergoing treatment. In practice, this is indicated by the substantially complete cessation of the evolution of hydrogen hallde. In general,

the halogen-content or chlorine-content of the final Product should be less than about 4% by weight.

' The following detailed examples are for the purpose of illustrating modes of preparing the synthetic drying oils of my invention, it being clearly understood that the invention is not to be considered as limited to the specific compositions disclosed hereinafter or to the manipulations and conditions set forth in the examples.

Exmtn 1 A fraction consisting largely of dimethyl and trimethyl naphthalenes was obtained by distillation from 2-pass synthetic crude tower bottoms from a Houdry operation. This fraction had the following physical properties:

Boiling range F 500-600 A. P. I. gravity 12.0 Specific gravity at 60 F 0.9861 Refractive index at 20 C 1.590 Mixed aniline No F 59 Aromatics per cent by volume 95-100 This fraction was subjected to an exhaustive catalytic hydrogenation using a Universal Oil Products nickel hydrogenation catalyst, at a temperature of 500 F. and a pressure of 1500 pounds per square inch (hydrogen pressure at room temperature). The product obtained had the following physical properties:

Boiling range F 420-550 A. P. I. gravity 1 31.0 Specific gravity at 60 F 0.8708 Refractive index at 20 C 1.4710 Aniline No F 140 Aromatics per cent 0 60 F. of 1.1.

580 grams of this product were placed in a flask equipped with a stirrer, mixed with 233 grams of calcium oxide, and then heated while stirring to a temperature of 220-230 C. A small stream of nitrogen was used to facilitate the removal of liberated gases. The mixture was stirred and kept at a temperature of 220-230 C. with stirring for a period of time of about ten hours, at the end of which, the evolution of hydrogen chloride practically ceased. The product thus obtained was filtered to remove the calcium oxide. An orange-green oil was obtained. This orangegreen oil had an iodine number of 101 and a chlorine-content of 1.2% by weight.

A film of this oil became dry to the touch in 48 hours. When 10 parts by weight of this oil were compounded with 0.35 part by weight of lead-manganese drier and 0.04 part by weight of' .ditions employed and the results obtained are set forth in Table 1. Corresponding data of Example 1 are also tabulated in Table I for purposes of comparison.

The entire 2-pass synthetic crude tower bottoms from Houdry operation, having the following physical properties:

Boiling range F 440-750 A, P. I. gravity I 7.6 Specific gravity at 60 F 1.1073 Mixed aniline No F.. 57 Aromatics per cent by volume 80-90 Boiling range F 418-680 A. P. I. gravity 25.! Specific gravity at 60 F 0.9001 Refractive index at 20 C 1.4830 Aniline No F 134 Aromatics per cent by volume 3.8

580 grams of this product were placed in a flask equipped with a stirrer. Chlorine was introduced into the stirred mixture at such a rate as to maintain the temperature at about 80 C. The flask was illuminated with a 200-watt light bulb to accelerate the chlorination. When the desired weight increase corresponding to a chlorin content of 28% by weight, was achieved, the product was cooled and blown with nitrogen to remove occluded gases.

580 grams of this product were placed in a flask equipped with a stirrer, mixed with 233 grams of calcium oxide, and then heated while stirring to temperature of 220-230" F. The mixture was stirred and kept at this temperature until the evolution of hydrogen chloride practically ceased. The product was filtered to remove the calcium oxide. The product had an iodine number of 94 and contained about 3.1% by weight of chlorine. A film of this product became dry hard after two days.

As stated hereinbefore, the products obtained from the entire bottoms also possess drying oil properties. However, the drying time of these products will be considerably longer than that of the. products obtained when the initial charge stocks consist, largely of alkyl naphthalenes.

The data set forth in Table II are given to illustrate and compare the drying oil properties of the products produced in accordance with the process of the present invention.

Table I Chlorine Chlorina- Dehydra- Yiel tion Texnin Alkyl halogena- Per Cent Iodine t? Pmm'a fie y $333 C. by weight Catalyst We ght l 80 26. 1 Ca() 88 101 Floor Floor 2 80 29.9 .do.- 87 109 BealerA Sealer-B 3 M iii ii iii I n 5:12:11 11 33? 30. 8 -..r o 75 86 hina-Wood Oil ..parts by weight.. 10 6 100 36. 7 n 73 56 Product of Exam le 1 do 10 7 70 25.0 r n 88 104 Lead-manganese rier..- do. 0.35 0.35 Cobalt Drier .do 0. 04 0.04 Arochem Resin #346. .do.... 6 d Solvent ("SOVABOU 410--.. 34.8 34. 6 Exams: 8 Dry Hard Time --hours-. 4 4

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiments 'he considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. The process of manufacturing synthetic drying oils, which comprises subjecting aromatic hydrocarbon material consisting largely of dimethyl naphthalenes and trimethyl naphthalenes, to exhaustive catalytic hydrogenation to yield a product consisting largely of alkyl decalins; halogenating the product of the exhaustive catalytic hydrogenation at temperatures varying between about 20 C. and about C. for a period of time suflicient to yield a halogenated product containing between about 25 per cent by weight and 35 per cent by weight of halogen; and dehydrohalogenating said halogenated product in the presence of a dehydrohalogenating catalyst for a period of time sufilcient to reduce the halogen-content of said halogenated product to less than about 4 per cent by weight.

2. The process of manufacturing synthetic drying oils, which comprises subjecting aromatic hydrocarbon material consisting largely of dimethyl naphthalenes and trimethyl naphthalenes, to exhaustive catalytic hydrogenation to yield a product consisting largely of alkyl decalins; 'chlorinating the product of the exhaustive catalytic hydrogenation at temperatures varying between about 20 C. and about 80 C. for a period of time sufllcient to yield a chlorinated product containing between about 25 per cent by weight and 35 per cent by weight of chlorine; and dehydrochlorinating said chlorinated product in the presence of a dehydrohalogenating catalyst for a period of time suflicient to reduce the chlorine-content of said chlorinated product to iins; chlorinating the product of the exhaustive catalytic hydrogenation at temperatures varying between about 30 C. and about 50' C. for a period of time sufilcient to yield a chlorinated product containing between about 25 per cent by weight and 35 per cent by weight of chlorine; and

9 dehydrochlorinating said chlorinated product in' product containing between about 25 per cent by weight and 35 per cent by weight oi. chlorine; and dehydrochlorinating said chlorinated product inthe presence of calcium oxide for a period of time suillcient to reduce the chlorine-content of go said chlorinated product to less than about 4 per cent by weight.

5. The process oi manufacturing synthetic drying oils, which comprises subjecting aromatic hydrocarbon material consisting largely of dimethyl napthalenes and trimethyl naphthaienes, to exhaustive catalytic hydrogenation to yield a product consisting largely of alkyl decalins; chlorinating the product or the exhaustive catalytic hydrogenation at temperatures varying so between about 30 C. and about 50 C. for a period 01 time sumcient to yield a chlorinated product containing between about 25 per cent by weight and 35 per cent by weight oi. chlorine; and

dehydrochlo'rinating said chlorinated product in 36 the presence of calcium oxide for a period of time sufllcient to reduce the chlorine-content oi-said chlorinated product to less than about 4 per centby weight.

6. A synthetic drying oil prepared by subjecting aromatic hydrocarbon material consisting largely of dimethyl naphthalenes and trimethyl naphthalenes, -to exhaustive catalytic hydrogenation tdyield a product consisting largely of alkyl decalins; chlorinating the product 01' the exhaustive catalytic hydrogenation. at temperatures varying between about C. and about 80 C. for a period of time sumcient toyield a chicrinated product containing between about per cent by weight and per cent by weight of chlorine; and dehydrochlorinating said chlorinated product in. the presence oi. calcium oxide for a period of time suillcient to reduce the chlorinecontent 01 said chlorinated product to less than about 4 per cent by weight.

- FERDINAND P. O'ITO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,254,866 Thiele Jan. 29, 1918 1,384,423 Bielouss -L. July 12, 1921 1,384,427 Gardner et al. July 12, 1921 1,582,310 Schroeter Apr. 27, 1926 2,216,131 Pier et al. Oct. 1, 1940 2,359,935 Nudenburg et al. Oct. 10, 1944 

